Water tube steam generator of the field tube type



June 17, 1952 w LEWIS 2,600,999

WATER TUBE STEAM GENERATOR OF THE FIELD TUBE TYPE Filed May 9, 194'? 4 Sheets-Sheet l W. Y. LEWIS June 17, 1952 WATER TUBE STEAM GENERATOR OF THE FIELD TUBE TYPE 4 Shees-Sheet 2 Filed May 9. 194'? June 17, 1952 w LEWls 2,600,999

WATER TUBE STEAM GENERATQR OF THE FIELD TUBE TYPE Filed May 9. 1947 4 Sheets-Sheet 5 June 17, 1952 w. Y. LEWIS 2,500,999

WATER TUBE STEAM GENERATOR OF THE FIELD TUBE TYPE Filed May 9, 1947 4 Sheets-Sheet 4 Patented June 17, 1952 ELN'T OFFICE WATER TUBE STEAM GENERATOR OF THE FIELD TUBE TYPE William Yorath Lewis, London, England, ass'ig'n'cr to Yorath Lewis Boilers Limited, London, England Application May 9, 1947, Serial No. 746;994 In Great Britain October 12, 1939 Section 1, Public Law 690, August 8, 1946 Patent expires October 12,1959

1 Claim. 1

This invention relates to Water-tube steam generators of the Field-tube type.

In such generators, positioning devices for the inner tubes or for groups of inner tubes of the Field-tubes have been proposed comprising a partition disposed within the drum and built up from a plurality of individual removable units into which the inner tubes pass.

The object of the present invention is to provide forms of such positioning devices which are cheap to construct and which enable ready attachment, detachment and removal of individual inner tubes or groups of inner tubes to be effected.

The invention consists in a steam generator having features as set out in the'claim appended hereto.

Referring to the accompanying diagrammatic drawings:

Figure 1 is a vertical cross-sectional view of part of the drum of a Field-tube steam generator embodying the present invention in one form.

Figure 2 is a plan view'thereof with certain parts removed.

Figure 3 is a plan view of the supporting frame, and

Figures 4, 5 and 6 are respectively elevational, cross-sectional and plan views of one of the trough end plates.

Figures 7 and 8 are plan views of the members formed by the trough side plates.

Figure 9 is an elevational view of the trough members.

Figures 10 and 11 are respectively front, elevational and end elevational views of an endplate screen, and

Figures 12 and 13 are respectively end elevational and plan views of an inner tube end screen.

In carrying the invention into efiect according to one form by way of example as illustrated in Figures 1 to 13, a steam generator having a steam drum a and banks of Field-tubes b is furnished with a positioning device in the drum, which positioningdevice comprises a plurality of mild steel bars 0 of rectangular cross-section.

Each side face of certain of the bars a is furnished with a plurality of semi-cylindrical notches d, each notch being in register with a similar notch in the adjacent bar.

The bars are supported in an angle frame 6 furnished with set screws 1 at one end abutting directly or indirectly the adjacent bar 0 and serving to clamp the bar against one another in a lateral direction.

The various holes formed by the co-operating notches d contain the upper ends of the inner 2 tubes or of the Field-tubes, the outer tubes it being secured to the drum a.

In order to -assemble the inner tubes g they may be placed in positionin respective outer tubes 71, and with the upper ends in register with the appropriate holes in the positioning device, the bars 0 are clamped together laterally so as to secure all the inner tubes inposition and to make a sufficiently water-tight joint around these tubes and between the bars.

In order to remove the 'inner tubes or any particular tube, itis merely necessary to slacken theset screws J and'to remove anadjacent'bar or bars 0.

The bars a form the floor of a central trough furnished with vertical side plates '2, i and this trough is contained within an outer trough furnished with vertical s'ide plates 7', 9'. The plates 7, are welded to strips 7c, is to formgrooved bases straddling ribs 0, o'welded to the drum a. At each end of the outer trough a vertical plate m is provided having an angle ledge member it upon which the frame e rests and each plate is'provided with welded strips is to straddle further curved ribs o not shown, welded to the drum.

One of the side plates 1 is rigidly secured to one of the side plates 7' by means of a bridge piece t to form a member as illustrated in Figures 7 and 8 and these two members are retained in position with their ends held between ribs q, 11, Figures 4, 5 and 6, on the end plates m by means of locking strips s Figure 2. The side plates i rest in slots formed by strips e welded to the frame e, Figure 1. The front ends of the trough members i, 7', Figures 7, 8 and 9, are reduced in height and closed by plates 25 whereas the rear ends of the trough members are open; these reduced ends facilitate access by way of the manhole u, Figure 1.

The openings pin the end plates m are occupied by A3 mesh wire sliding screen plates 0', Figures 10 and 11, and the upper ends of the tubes g are covered by a wire gauze screen w of similar mesh Figures 12 and 13.

An open-ended cover a: is provided spanning both outer and inner troughs, it being found in practice that deposits tend to take place on the flat top thereof whence they may be removed periodically.

Feed water is admitted to the inner trough and steam emerging into the space 1, Figure 1, passes up by way of the spaces 2, 2 into the space 2 whence it passes above the water level to the steam outlet duct of the drum.

It will be noted that the space 2 is wider than the space z, Figures 1, 7 and 8, and the reason for this is that in the particular example illustrated there happens to be five rows of main Field-tubes marked 3, 4, 5, 6 and I in Figure l and the upper ends of the inner tubes 9 of rows 3 and 4 lie in a single row to the left of Figure 2 whereas the upper ends of the inner tubes 9 of rows 5 and 6 and of row I lie in two separate rows to the right of Figure 2; the arrangement thus happens to be unsymmetrical.

If the axes of the sockets formed by the notches in the positioning device are at right angles to the lower surface thereof as in the example illustrated, the inner tubes will lie in a direction which is normal to the positioning device, but if desired the axes of the sockets may be inclined at any convenient angle to the plane of the positioning device. By this means if desired the inner tubes may enter the positioning device without being in bent condition.

In the example described above, several inner tubes are clamped between each pair of bars, but if desired only a single tube may be embraced by a pair of bars or blocks.

In some cases packing material may be used 4 to improve the water tightness and/or steam tightness of the joints between the bars and tubes and between the bars and their supporting structure.

Instead of making the bars of rectangular I claim:

A steam generator including a steam and Water drum, steam raising Field-tube units each comprising inner and outer tubes depending from said drum, said outer tubes being connected to said drum and communicating therewith,

, said inner tubes projecting beyond the terminal ends of said outer tubes, a combined feed water receiving and steam conveying trough within the drum, said trough including spaced pairs of parallel side walls comprising adjacent inner walls and an outer wall spaced from each inner wall defining an inner feed water channel between the inner wall and an outer steam receiving channel between each inner wall and each outer Wall, said inner tubes projecting within said feed water channel, a bottom for said feed water channel comprising a plurality of members having complementary notches on opposite edges corresponding in contour to the external contour of said inner tubes, a frame supported at the lower ends of the adjacent inner walls and removably supporting said members, said members being disposed in abutting relationship andembracing said inner tubes, clamping means maintaining the said members in position and means between the drum and said outer walls for supporting the trough.

WILLIAM YORATI-I LEWIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,068,187 Lewis Jan. 19, 1935 FOREIGN PATENTS Number Country Date 26,759 Great Britain Nov. 25, 1896 656,643 France Jan. 2, 1929 

